Circuit breaker trip mechanism



May 25, 1965 R. BUYS ETAL 3,185,792

CIRCUIT BREAKER TRIP MECHANISM Filed May 24, 1961 2 Sheets-Sheet 1 INVENTORS GEORGE R. BUYS,

Gmasm H. N ETTLETON A TTORNEY May 25, 1965 R. BUYS ETAL CIRCUIT BREAKER TRIP MECHANISM 2 Sheets-Sheet 2 Filed May 24, 1961 INVENTORS GEORGE. RBuYs, Gmszm' H. NETTLETON BY F cw A T TORNEY United States Patent 3,185,792 CIRUUIT BREAKER TRIP MECHANISM George R. Buys, Denver, Cola, and Gilbert H. Nettleton,

Plainville, Conn, assignors to General Electric Company, a corporation of New York Filed May 24, 1961, Ser. No. 112,281 4 Claims. (Cl. 200-116) Additionally, magnetic or instantaneous acting tripping means is ordinarily included for causing automatic contact opening in response to overload currents of short circuit magnitude such, for example, as currents of five or more times the circuit breakers nominal current rating. A pivotally mounted trip bar is usually provided adjacent both the thermal and the magnetic tripping means and is operatively connected to the circuit breaker contacts so that a predetermined movement of the trip bar will release the contacts and permit opening thereof. Both the thermal and the magnetic tripping means are movable in response to their selected current measuring conditions so as to move into engagement with the trip bar and move it the predetermined distance to cause contact opening upon the occurrence of a suficiently abnormal current condition. The particular value at which thermal tripping occurs is pre-set when the breaker is manufactured and, for safety reasons, should not be changed during use. In the case of the magnetic or instantaneous tripping, however, it is desirable that the maximum and minimum instantaneous tripping points he set by the manufacturer, but that a certain latitude of adjustment be permitted the user. Accordingly, an adjusting means is generally provided for permitting adjustments within the range between the maximum and minimum tripping points.

In order to provide for proper functioning of such adjusting means and to permit compact positioning of the various elements within the trip unit, the trip bar is sometimes required to be a very irregularly shaped piece. In the past, the trip bar has been molded in one piece. Because of the irregular shape of the trip bar, however, warpage of the bar when molded often occurs, with the result being that accuracy of calibration is adversely affected. In addition, the trip bar maybind on its bearings and no longer pivot freely. Also, the ir-' regular shape of the trip bar results in a fragile structure which will break relatively easily in shipment or when subjected to shock loads in high shock applications.

Accordingly, it is a primary object of this invention to provide a circuit breaker having an improved molded trip bar which will not be easily subject to warpage or breakage.

Another object of this invention is to provide a molded trip bar in which warpage due to molding is held to a practical minimum and in which any warpage Which may occur does not adversely aiiect the pivotally movement of the trip bar.

A further object of this invention is to provide a trip bar of molded insulating material which is of irregular shape, butwhich is not highly susceptible to breakage during shipment or use.

A still further object of this invention is to provide a molded trip bar which is simple, inexpensive and easy to manufacture. I

Briefly stated, inaccordance with the invention in one form, a molded trip bar is provided comprising a plurality of separate, but loosely interengaging elements and pivotally mounted adjacent automatic tripping means in the same manner as the unitary trip bar usually utilized by prior art devices. Thermal and magnetic automatic tripping means are positioned adjacent each of the trip bar elements so that each moves into engagement with the corresponding trip bar element upon the occurrence of a sufficiently abnormal current condition. The trip bar elements are loosely interengaged so that the movement of any one of the elements in response to an abnormal circuit condition is transmitted to a selected one of the elements to cause tripping.

While the specification concludes with claims particularly pointing out and distinctly claiming the subject matter of the invention, it is believed that the invention will be better understood from the following description taken in connection With the accompanying drawings in which:

FIGURE 1 is a side elevation view, partly in section, of an electric circuit breaker incorporating the invention;

FIGURE 2 is a section view along line 22 of FIG- URE l of a circuit breaker trip unit constructed in accordance with the invention;

FIGURE 3 is a side View of a portion of the automatic tripping mechanism of the circuit breaker trip unit shown in FIGURE 2;

FIGURE 4 is a sectional view of the circuit breaker trip unit taken along line 44 of FIGURE 2;

FIGURE 5 is a perspective view of a portion of the trip mechanism comprising interengaged elements shown positioned adjacent thermally actuated tripping means;

FIGURE 6 is an elevation view of the trip bar elements of FIGURE 2.

Referring first to FIGURE 1, a three-pole electric circuit breaker is shown having an insulated outer casing comprising a base 10 and a cover 11. One of three load terminals 12 is shown at one end of the base 10. A removable trip unit 13 is mounted within the outer casing adjacent the load terminals 12 and is electrically connected to the load terminals 12 by means of conductor straps 14 and to the circuit breaker contacts 15 by c011- ductor straps 16.

The circuit breaker includes an operating mechanism 17 which may be conventional. The operating mechanism includes a handle 18 for manually moving the contacts 15 between open and closed circuit positions. In i addition to manually opening the contacts by means of the handle 18, the contacts 15 may be opened automatically in response to predetermined abnormal circuit conditions. The contacts 15 will open automatically when releasable member 20 shown in FIGURE 3 is allowed to move in a clockwise direction or upwardlyas viewed in FIGURE 3. The member 20, which is biased in the clockwise or contact opening direction is generally held in a latched position as shown by an intermediate latch member 21. Upon the occurrence of a predetermined current condition in the circuit breaker, the intermediate latch member 21 is released to turn in a counterclockwise direction, thereby releasing member 20 so that contact opening will result. An automatic tripping mechanism of the type in which the present invention is embodied is fully described in Patent No. 2,884,497 to H. M. Steven etal., assigned to the same assignee as the present invention.

The intermediate latch member 21 is pivotally and slidabiy supported on a pin 22 and is biased in a clockwise direction by a biasing spring 23. When in the latched position shown in FIGURE 3, however, the biasing force exerted on the latch 21 by the releasable member 20 is substantially greater than the force exerted by the biasing spring 23. In order to prevent counterclockwise movement of the latch 21, latch cam surface 31 contacts a roller 36 positioned at the top of a latch 26 pivotally mounted on the trip unit housing shown in FIGURES 4 and 5. Under normal circuit conditions, the latch 26 and the roller are held in the position shown in FIG- URE 3 by means which will be more fully described below, Upon occurrence of a predetermined abnormal current condition, however, the latch 26 and the roller 36 may move to the left as viewed in FIGURE 3, thus releasing the intermediate latch 21 which will turn counterclockwise and, in turn, release member 26. Automatic opening of the circuit breaker contacts will result.

The latch 26 is pivotally supported on a pin 27 passing through aligned openings in a boss 23 molded integral with the trip unit housing 25. At the upper end of the latch 26 as viewed in FIGURE 3, a pin 29 extends between spaced apart portions of the latch 26 and the roller 30 is mounted on the pin 29. The cam surface SI bearing on the roller 36 will tend to move the latch 26 to the left as viewed in FIGURE 3. In order to prevent undesired movement of the latch 26, a toggle linkage comprising toggle links and 36 is provided between the pin 29 at the top of latch 26 and a relatively stationary pivot pin 37 carried by the trip unit housing 25. The links, which are joined to each other by a knee pivot pin 38, are biased upwardly by a spring 39. Upward collapse of the linkage which would permit latch 26 to move to the left and cause automatic opening of the circuit breaker contacts 15 is prevented by an adjustable screw 4%) carried by a trip bar assembly 44 to be described.

On the occurrence of predetermined current conditions, the adjusting screw :0 carried in the boss 41 is moved in a manner to be described, and moves the toggle links 35 and 36 downwardly. Once the adjusting screw has pushed the linkage through its center position, the force exerted on the roller 36 by the cam surface 31 causes the link 26 to move in the counterclockwise direction or to the left so as to collapse the linkage downwardly. When the roller 30 moves to the left, the intermediate latch 21 moves in a counterclockwise direction and permits the releasable member 20 to move upwardly to cause automatic opening of the contacts 15.

Referring particularly to FIGURES 2 and 5, it will be seen that in accordance with the invention a trip bar assembly 44 is provided comprising three discrete elements 45, t6 and 47 as best shown in FIGURE 2 and FIGURE 6. Each trip bar element is pivotally supported on a separate pivot pin 37A, 37B, and 37C respectively. The central trip bar element has axially extending projections 48 and 49 on its ends which are in overlapping relation to projections 56 and SI carried by the outer trip bar elements 46 and 47, respectively. The overlapping relation of the projections is such that the central element 45 may be moved to the right or in a clockwise direction as viewed in FIGURE 3 without causing corresponding movement of either of the outer elements 46 and 47. If either of the outer elements 46 and 4-7 are moved in the clockwise direction as viewed in FIGURE 3, however, the interengaging projections will cause the central trip bar element 45 to also move in the clockwise direction.

The central trip bar element 45 is biased in a counterclockwise or non-operating direction by a compression spring 59. This urges the projection 49 of the element 45 into engagement with the projection SI of the outer element 47. counterclockwise motion of the element 47 is limited, however, by an adjustable stop screw 42 carried by the insulating housing. Thus the screw 42 serves to determine also the extreme counterclockwise position of the central element 45, as well as the outer element 47. The normal position of the outer element 46 is determined by the projection 48, which limits its free travel in one direction, and by the calibrating screw 65A of the bi metallic strip 65.

Since each of the bimetallic strips 55, 65, 66 is provided with its own calibrating screw A, A, 66A, respectively, it will be observed that each may be adjusted separately. It is therefore not necessary that the corresponding engaged points on the trip bar assembly 44 be in alignment, or in any predetermined fixed relation.

As best shown in FIGURE 4, conductor straps 14 and I6 joining each of the load terminals 12 to the circuit breaker contacts 15 shown in FIGURE 1 form with central heater sections continuous electric paths through the trip unit housing 25. The central heater section 58 shown in FIGURE 4 which is one of three similar heaters in the circuit breaker is formed in a loop of reduced crosssection which will heat up in response to the passage of electric current through the circuit breaker. A bimetallic strip member 55 best shown in FIGURE 3 is positioned adjacent the heater section shown and is secured by proper fastening means to the conductor strap 16. A similar bimetallic strip is positioned adjacent each of the other heaters. As current increases through the heater section 58, the temperature rises and causes the bimetallic strip 55 to deflect to the right as viewed in FIGURE 3. A calibrating screw 5'7 carried at the upper end of the bimetallic strip 55 contacts the adjacent central trip bar element 45 as the bimetallic strip moves to the right and causes the trip bar element 45 to move in the clockwise direction. Since similar bimetallic strips 65 and 66 are positioned adjacent the outer trip bar elements 46 and 47, respectively, as shown in FIGURE 2, excessive temperature in any one of the three heater sections will cause one of the trip bar elements to move in the clockwise direction. As pointed out above, clockwise movement or" either of the outer trip bar elements 46 and 47 as viewed in FIGURE 3 causes a corresponding movement of the central trip bar element 45. As the central element i5 moves in the clockwise direction in FIGURE 3, the adjusting screw 46 forces the toggle linkage downwardly to allow the latch 26 to move to the left so as to result in automatic opening or" the contacts 15. Since the temperature in the circuit breaker should not exceed a predetermined maximum, the setting of the calibrating screw 57 is determined before the circuit breaker is placed in operation and the screw is locked in position by suitable locking means.

Following the opening of the circuit breaker contacts I5, the temperature within the trip unit housing will cool, thus allowing the bimetallic strip 55 to move to the left to its original position shown in FIGURE 3. Spring 56 shown in FIGURE 5 causes the central trip bar element 45 to return in a counterclockwise direction to the position shown in FIGURE 3 as the calibrating screw 57 is withdrawn. In the event that either of bimetallic strips 65 and 66 causes the automatic opening, spring 50 will cause the corresponding outer trip bar element to return in a counterclockwise direction along with the central trip bar element 45. As screw 40 on the central trip bar element 45 is withdrawn from its contact with the toggle linkage, spring 39 biases the toggle links 35 and 36 upwardly so that latch 26 is moved to the right. The contacts 15 may then be manually reset. During the manual resetting operation, the intermediate latch 21 pivots and slides about the pin 22 so as to permit the resetting of the releasable members 26.

Occasionally, currents of short circuit magnitude may occur in the circuit breaker. In order to protect the circuit, it may be desirable to open the'circuit instantaneously without waiting for the thermal sensor described above to function. To provide for instantaneous opening, a U-shaped stationary magnet 70 as shown in FIGURE 3 is provided in a surrounding relation with the heater section 56 so that the current passing through the heater 58 creates a magnetic field in the surrounding magnet 60. A magnetic armature 71 is provided adjacent the stationary magnet 60, the armature being pivotally supported on the axis of the pivot pin 37. Similar magnets and armatures are positioned adjacent each of the other heaters. The armature 71 is biased at all times in a counterclockwise direction as viewed in FIGURE 3 by a spring biasing means not forming part of this invention (not shown) against an adjustable stop screw 72. When the magnetic force, which is proportional to the current flowing in the heater section 58, exerted by the magnet 70 on the armature 71 is great enough to overcome the movement of the spring biasing force, the armature 71 moves to the left or in the clockwise direction as viewed in FIGURE 3 into engagement with the magnet 79. As the armature 70 moves to the left, a projection on the armature engages the central trip bar element 45 so as to cause clockwise movement of the central trip bar element 45. The adjusting screw 49 therefore moves the toggle links 35 and 36 downwardly so as to cause link 26 to move to the left, thereby releasing member and resulting in automatic opening of the circuit breaker contacts 15. In the event that one of the armatures adjacent the outer trip bar elements 46 and 4-7 reacts to an overload current, the outer element tripped by its respective armature will cause the central trip bar element 45 to move clockwise as viewed in FIGURE 3 so as to cause automatic contact opening.

In order to provide for easy adjusting of the biasing means, slots 63 are provided in the trip unit housing as shown in FIGURE 2 through which adjustable levers 63A (see FIG. 4) attached to the armature biasing springs (not shown) may extend. By moving one of the levers, 63A, the line of action of the corresponding spring force may be moved closer to or farther from the axis of the pivot pin of the corresponding armature. In order for the line of action to closely approach the axis, deep notches 51 are provided in the trip bar assembly 44 as shown in FIGURE 5.

Following the opening of the circuit breaker contacts 15, the biasing moment on the armature 71 causes counterclockwise movement of the armature into engagement with adjustable stop screw 62. Similar biasing means causes the return of the other armatures to their similar normal positions. As the armature 71 returns to the position shown in FIGURE 3, the spring 5%) shown in FIGURE 5 causes the trip bar elements to return in a counterclockwise direction to their original position shown in FIGURE 3. As screw on the central trip bar element 55 is withdrawn from its contact with the toggle linkage, spring 39 biases the toggle links 35 and 36 upwardly so that latch 26 is moved to the right. The contacts 15 may'then be manually reset.

Because of the loose connections shown in FIGURE 2 between the projections 48 and 49 of the central trip bar element with the projections 50 and 51 of the outer trip bar elements 46 and 47 respectively, it will be obvious that the warpage which may occur during or following the molding of the trip bar elements 45, 46 and 4'7 will be taken up in the joints between the trip bar elements and not be transmitted to the trip bar bearings. Also, since each element is supported on its own relatively short pivot pin, bending is not likely to occur despite slight warpage of the individual elements.

As pointed out above, the trip bar elements 45, 46 and 47 are provided in the embodiment shown with integral overlapping projections 48, 49, 59 and 51 at their ends which are interengaged so that clockwise movement of one of the outer elements 46 and 47 will cause a corresponding clockwise movement of the central trip bar element 45, but not of the other outer element. A counterclockwise movement of the central element 45 will cause counterclockwise movementof both of the outer elements 46 and 47. It will be appreciated, however, that the invention may also be practiced by any suitable means of interconnecting the ends of a plurality of trip bar elements so that movement of any one element will result in the movement of aselccted trip bar element. Therefore, it will be seen that it would be within the spirit of the invention to provide projections which would, under all conditions, compel simultaneous movement of all of the trip bar elements. We prefer, however, to

provide the oneway type of connection described in order to minimize the work required of the bimetallic strips 55, 65, 66, and also to make for easier assembly of the parts.

While only one embodiment of the invention has been described in detail, it will be readily apparent that various modifications thereof may be made, and it is intended to cover by the appended claims all such modifications as fall within the true spirit and scope of the invention.

What we claim as new and desire to secure by Letters Patent of the United States is:

1. An electric circuit breaker comprising:

(a) an insulating casing,

(b) at least one pair of relatively movable contacts sup orted in said insulating casing.

(c) trip means supported in said insulating casing and connected to said relatively movable contacts,

(d) first and second discrete trip bar elements pivotally supported in said insulating casing for rotation about a common axis,

(e) first current responsive means mounted in said insulating casing and acting on said first trip bar element to rotate said first trip bar element in a predetermined directio-n upon the occurrence of predetermined current conditions,

(f) means connecting said first trip b-ar element to said trip means to move said trip means in a direct-ion to cause opening of said relatively movable contacts upon movement thereof in said predetermined direction,

(g) second current responsive means supported in said insulating casing and acting on said second trip bar element to rotate said second trip bar element in said predetermined direction upon the occurrence of predetermined current conditions, A

(h) interconnecting means for said trip bar elements comprising an axially extending inte ral portion on said first trip bar element eccentric to said common axis extending toward said second trip bar element and an axially extending integral portion on said said first trip bar element eccentric to saidcommon axis extending toward said first trip bar element and overlapping said axially extending portion of said first trip bar element, said axially extending portion of said first trip bar element being closely adjacent said axially extending portion of said second trip bar element at the side thereof in the tripping direction whereby any substantial rotation of said second trip bar element in said tripping direction causes substantially equal rotation of said first trip bar element in said direction, said extending portions being dimensioned to provide clearance between said portions at the side of said axially extending portion of said first trip bar element in said tripping direction to permit rotation of said first trip bar element in tripping direction at least to trip operating position without rotation of said second trip bar element thereby.

2. An electric breaker comprising:

(a) an insulating casing,

(b) at least one pair of relatively movable contacts mounted in said insulating casing,

(c) trip means mounted in said insulating casing and connected to said relatively movable contacts,

(d) a first trip bar element pivotally supported in said insulating casing, A

(e) second and third trip bar elements mounted in said insulating casing in axial alignment with and on opposite sides of said first trip bar element,

( first current responsive means mounted in said insulating casing and acting on said first trip bar element to move said element in a predetermined direction upon the occurrence of predetermined current conditions therethrough,

(g) said first trip bar element acting on said trip means '2" upon rotation of said first trip bar element in said predetermined direction and moving said trip means in a direction to cause opening movement of said contacts,

(/1) second and third current responsive means mounted in said insulating casing and acting on said second and third trip bar elements respectively to move said elements in said predetermined direction upon the occurrence of predetermined current conditions therethrough respectively,

(i) interconnecting means for said trip bar elements comprising a pair of oppositely extending integral portions of said first trip bar element eccentric to said common axis and an axially extending integral portion on each of said second and third trip bar elements eccentric to said common axis, said axially extending portions of said second and third trip bar elements overlapping the corresponding extending portions of said first trip bar element,

(1') said axially extending portions of said first trip bar element being closely adjacent said portions of each of said second and third trip bar elements at the side thereof in the direction of tripping rotation, whereby any substantial rotation of said second or third trip bar elements in tripping direction causes substantially equal rotation of said first trip bar element in said direction,

(it) said overlapping portions of said trip bar elements being dimensioned to provide clearance between said overlapping portions at the side of said first portion in tripping direction to permit rotation of said first trip bar element at least to trip operating position Without rotation of said second and third trip 'bar elements thereby.

3. An electric circuit breaker comprising:

(a) an insulating casing,

(17) at least one pair of relatively movable contacts mounted in said insulating casing,

(c) trip means mounted in said insulating casing and connected to said relatively movable contacts to cause opening of said contacts upon movement of said trip means in tripping direction,

(d) a first trip bar element,

(e) a first pin pivotally supporting said first trip bar element in said insulating casing,

(f) second and third trip bar elements supported in said insulating casing at opposite ends of said first trip bar element,

(g) second and third pins pivotally supporting said second and third trip bar elements in said insulating casing, said first, second and third pivot pins being substantially aligned axially,

(h) first current responsive means mounted in said insulating casing and acting on said first trip bar element to move said first trip bar element in a predetermined direct-ion upon the occurrence of predetermined current conditions therethrough,

(i) said first trip bar element acting on said trip means upon rotation of said first trip bar element in said predetermined direction and causing movement of said trip means in said tripping direction,

(j) second current responsive means mounted in said insulating casing and acting on said second trip bar element and moving said second trip bar element in said predetermined direction upon the occurrence of predetermined current conditions therethrough,

(k) third current responsive means mounted in said insulating casing and acting on said third trip bar element and moving said third trip bar element in said predetermined direction upon the occurrence of predetermined current conditions therethrough,

(l) interconnecting means for said trip bar elements comprising an axially extending portion on said first trip bar element eccentric to said first pin and an axially extending portion on each of said second 3 and third trip bar elements eccentric to said second and third pins, said axially extending portions of said second and third trip bar elements overlapping the corresponding axially extending portion of said first trip bar element,

(m) said axially extending portions of said first trip bar element being closely adjacent said axially extending portions of said second and third trip bar elements at the side thereof in tripping direction whereby any substantial rotation of said second and third trip bar elements in said tripping direction causes substantially equal rotation of said first trip bar element in said direction, said extending portions being dimensioned to provide clearance between said portions at the side of said extending portions of said trip bar element in said tripping direction, to permit rotation of said first trip bar element in tripping direction at least to trip-operating position without rotation of said second and third trip bar elements thereby.

4. An electric circuit breaker comprising:

(a) an insulating casing,

(b) at least one pair or" relatively movable contacts mounted in said insulating casing,

(c) trip means mounted in said insulating casing and connected to said contacts to cause opening of said contacts upon movement of said trip means in tripping direction,

(d) first and second elongated trip bar elements of molded plastic insulating material pivotally supported in said insulating casing for rotation about a common axis,

(2) first current responsive means mounted in said insulating casing and acting on said first trip bar element to move said first trip bar element in a predetermined direction upon the occurrence of predetermined current conditions therethrough,

(1) said first trip bar element acting on said trip means upon rotation of said first trip bar element in said predetermined direction to move said trip means in said tripping direction,

(g) second current responsive means mounted in said insulatin casing and acting on said second trip bar element to move said second trip bar element in said predetermined direction upon the occurrence of predetermined current conditions therethrough,

(h) interconnecting means for said trip bar elements comprising an axially extending integral portion on said first trip bar element eccentric to said common axis and an axially extending integral portion on said second trip bar element eccentric to said common axis,

(i) said axially extending portions of said first trip bar element being closely adjacent said axially extending portion of said second trip bar element at the side thereof in tripping direction, whereby any substantial rotation of said second trip bar element in said tripping direction causes substantially equal rotation of said first trip bar element in said direction, said extending portions being dimensioned to provide clearance between said portions at the side of said first portion in tripping direction to permit rotation of said first trip bar element in tripping direction at least to trip-operating position without rotation of said second trip bar element thereby.

References Cited by the Examiner UNITED STATES PATENTS 1,869,563 10/30 Jennings 2001l6 2,797,277 9/54 Dorfman ZOO-88 2,884,497 8/57 Stevens et a1. 200-88 BERNARD A. GILHEANY, Primary Examiner.

75 ROBERT K. SCHAEFER, Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,185,792 May 25, 1965 George R. Buys et a1.

It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 6, line 40, strike out "said"; line 41, for "first" read second Signed and sealed this 5th day of October 1965.

(SEAL) Altest: A

EDWARD J BRENNER ERNEST W. SWIDER Commissioner of Patents Attesting Officer 

1. AN ELECTRIC CIRCUIT BREAKER COMPRISING: (A) AN INSULATING CASING, (B) AT LEAST ONE PAIR OF RELATIVELY MOVABLE CONTACTS SUPPORTED IN SAID INSULATING CASING. (C) TRIP MEANS SUPPORTED IN SAID INSULATING CASING AND CONNECTED TO SAID RELATIVELY MOVABLE CONTACTS, (D) FIRST AND SECOND DISCRETE TRIP BAR ELEMENTS PIVOTALLY SUPPORTED IN SAID INSULATING CASING FOR ROTATION ABOUT A COMMON AXIS, (E) FIRST CURRENT RESPONSIVE MEANS MOUNTED IN SAID INSULATING CASING AND ACTING ON SAID FIRST TRIP BAR ELEMENT TO ROTATE SAID FIRST STRIP BAR ELEMENT IN A PREDETERMINED DIRECTION UPON THE OCCURRENCE OF PREDETERMINED CURRENT CONDITONS, (F) MEANS CONNECTING SAID FIRST TRIP BAR ELEMENT TO SAID STRIP MEANS TO MOVE SAID TRIP MEANS IN A DIRECTION TO CAUSE OPENING OF SAID RELATIVELY MOVABLE CONTACTS UPON MOVEMENT THEREOF IN SAID PREDETERMINED DIRECTION, (G) SECOND CURRENT RESPONSIVE MEANS SUPPORTED IN SAID INSULATING CASING AND ACTING ON SAID SECOND TRIP BAR ELEMENT TO ROTATE SAID SECOND STRIP BAR ELEMENT IN SAID PREDETERMINED DIRECTION UPON THE OCCURRENCE OF PREDETERMINED CURRENT CONDITIONS, (H) INTERCONNECTING MEANS FOR SAID STRIP BAR ELEMENTS COMPRISING AN AXIALLY EXTENDING INTEGRAL PORTION ON SAID FIRST TRIP BAR ELEMENT ECCENTRIC TO SAID COMMON 